Dry buttermilk powders are on the market today, but they are mostly spray dried, natural, cultered buttermilk to which amounts of other ingredients have been added. Conventionally, the taste and texture of such products are poor. The reason for this is that the buttermilk, as with other milk products, loses a lot in the spray drying process due to the heat employed. Off-flavors are developed, and reconstitution with milk or water becomes difficult. Even with the addition of imitation or natural flavors, the off-flavors are difficult to mask, and the tendency to form a curdy mass makes it difficult to obtain a product having the body, texture and consistency of natural buttermilk.
For purposes of the present application, the term "natural buttermilk" refers to cultured buttermilk produced by the addition of bacterial cultures to skim milk, or acidified milk produced by the direct acidification of skim milk.
A major problem in making a tart-tasting product from an acid-containing dry mix, by reconstitution with milk, is that the pH of the milk is lowered below the isoelectric point of the protein in the milk product, causing curdling. This problem is alluded to in an Eskritt et al U.S. Pat. No. 3,955,009, which proposes that with a pregellatinized starch and a hydrocolloid gum, the curdling can be avoided. It is indicated that the pregellatinized starch permits such rapid rehydration and quick setting that the coagulation and curdling of the milk proteins is prevented. The patent is not concerned with preparation of an imitation buttermilk, but rather is concerned with the preparation of an imitation yogurt, which would have a spoonable thickness or viscosity substantially higher than that of an easily pourable, buttermilk-type product.
The principal ingredients in the Eskritt et al patent are sucrose, pregellatinized starch, citric acid, emulsifier and guar gum.
Other patents dealing with reconstitution of acid-containing dry mixes with milk include Gardiner U.S. Pat. No. 3,917,875; Igoe U.S. Pat. Nos. 3,996,390, 4,058,636, and 4,169,854; Haber U.S. Pat. Nos. 4,081,566 and 4,081,567; and Sirett et al U.S. Pat No. 4,264,638.
Serafino et al U.S. Pat. No. 4,187,326, describes a dry beverage mix clouding agent containing maltodextrin and smaller amounts of xanthan gum and titanium dioxide. An aqueous solution of the maltodextrin, xanthan gum and titanium dioxide is spray dried. It is indicated in the patent that the co-drying prevents precipitation of the titanium dioxide when the dry mix is hydrated. The beverage dry mix is intended to be dispersible in water to provide opacity. The mix is not reconstituted with milk, and when reconstituted with water, has little or no effect on viscosity.
Smith U.S. Pat. No. 4,288,464 describes a flavor enhancer composition intended to be added to foods, including beverages, to enhance their flavor. The flavor enhancer comprises a watersoluble carbohydrate, a sugar, and maltol, all of which are co-dried. An example of one water soluble carbohydrate, given in the patent, is Maltrin 10, described as a hydrolyzed cornstarch having a dextrose equivalent of about 10.